This application from the Chicagoland Metropolitan AsthmaNet Consortium (OMAG) is in response to the RFA entitled Clinical Centers for the NHLBI Asthma Network (AsthmaNet). The Chicago Metropolitan area has more than 6 million inhabitants who are racially and ethnically diverse. The City of Chicago, which represents about half of this population, has high asthma prevalence rates in both children and adults (exceeding 10% in both groups) and has one of the highest asthma mortality rates in the United States. The CMAC includes academic medical center partners: Northwestern University, the University of Chicago, Children's Memorial Hospital, and John H. Stroger Hospital, and an expansive network of Community Partners. The CMAC is uniquely qualified to participate in AsthmaNet and contribute to the development and successful completion of the network clinical trials and proof of concept/mechanistic studies. This is based on the key personnel having extensive experience in asthma clinical and translational research, including studies exploring its pathophysiology, pathogenesis (genetic and environmental factors), epidemiology and treatment; leadership roles in key research support (including CTSA-funded) programs at their respective institutions; successfully worked together on several asthma research programs: access to a large, diverse asthma population; and successfully enrolled patients and control subjects in NIH, foundation and industry sponsored asthma research studies and clinical trials. The studies proposed address several important issues including: treatment approaches to adult asthmatics who smoke; the role of aggressive pre-treatment in pediatric asthmatics prior to the exacerbation season; the expression of HLA-G, a non-classical MHC antigen, in seasonal asthma exacerbations; and the incidence of obstructive sleep apnea (OSA) in asthmatic children and whether treatment of OSA improves asthma symptoms, quality of life and lung function. Participation by the CMAC will strengthen AsthmaNet and increase the likelihood that it will achieve its goal to address the most important asthma management questions and new treatment approaches in pediatric and adult asthma and inform clinical practice and future updates to the NAEPP guidelines.